Apparatus for recording and reproducing sound



.June 28, E c p 1,865,171

APPARATUS FOR RECORDING AND REPRODUCING SOUND Filed May 5, 1928 2Sheets-Sheet l 5+ c- 6+ c- C+ 67 4.5 9 40 gvwemtoz M 8, wa

WMWQLM- June 28, 1932. CHIPMAN 1,865,171

APPARATUS FOR RECORDING AND REPRODUCING SOUND Filed May 5, 1928 2Sheets-Sheet 2 awuemtoz Ill for reproducing purposes.

. faithfully reproduced.

Patented June 28, 1932 UNITED STATES PATENT OFFICE HARRY E. CHIPMAN, OFSPRINGFIELD, MASSACHUSETTS, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS,TO ANDREW LE ROY CHIPMAN, OF NEW YORK, N. Y.

APPARATUS FOR RECORDING AND REPRODUCING SOUND Application filed May 3,1928. Serial No. 274,775.

This invention relates generally to an apparatus for recording andreproducing sound, and more particularly to an apparatus adapted toreceive radio waves, permanently record, on a wire, magnetic impressionsderived from either radio waves or sound waves, and reproduce from themagnetic impressions, however received, 1mpressed upon the wire, soundsof audible form broadcast through the output end of the radio receivingapparatus.

A need has arisen for some reasonably cheap and effective means by whichan individual can permanently record the choicer and more appealingradio programs, and reproduce them at any time thereafter. An object ofthis invention, therefore, is to provide an apparatus by means of whichradio waves may be received and the sound characteristics thereofpermanently recorded Another object of this invention is to provide anapparatus by means of which the characteristics of all sounds may bepermanently recorded and Another object of this invention is to devisean apparatus by means of which recorded sound impressions, obtained byradio or otherwise, may be reproduced and broadcast through the outputend of my radio receiving apparatus.

Other objects of this invention will become obvious as the disclosureproceeds.

In order that a clearer understanding of my invention may be had,attention is hereby directed to the accompanying drawings,

forming a part of this application and illustrating certain possibleembodiments of this invention.

Referring to the drawings, Fig. 1 is a diagrammatical view of a portionof the apparatus, more particularlythat portion of the apparatusoperative to receive radio waves and transform them into a pulsatingcurrent of audio frequency; and I Fig. 2 is a diagrammatical view ofthat portion of the apparatus adapted to permanently record either thecharacteristics-of sounds directly or the characteristics of thepulsating radio waves, including means for translating the recordedsoundor current characteristics into such a form as to be reproduciblefrom the loud speaker of the radio receiving apparatus.

Referring to Fig. 1 of the drawings, radio frequency energy receivedupon the antenna 1 of any desired characteristics is directed throughthe transformer 2, comprising the usual primary and secondary windings,through wire 3 to ground at 4:. The energy transferred to the secondarywinding leaves the transformer 2 through terminal 5, and is directedthrough a grid resistor 6 to the grid electrode of a three electrodevacuum tube 9. The frequency of the received si nal may be controlled bythe usual tuning means, such as has been conventionally illustrated bythe variable capacity condenser 7 shunting the secondary of thetransformer. In parallel'with the condenser 7 I have placed a smallcapacity condenser 8, which may serve as a Vernier to establish finetuning.

Output energy leaves the plate of vacuum tube 9, passes throughconductor 10 and through the primary winding of transformer 11. Energytransferred to the secondary Winding of transformer 11 leaves thetransformer through terminal 12, and is directed through the usual gridresistor 13 to the grid electrode of vacuum tube 14. The usual tuningcondenser 15 is associated with the secondary of transformer 11. A smallcapacity condenser 16 is connected between the primary and secondarywindings of transformer 11 for the purpose of neutralization.

Output energy from the plate of vacuum tube 14 passes through conductor17 and through the primary winding of transformer 18. Energy transferredto the secondary winding leaves the transformer 18 through terminal 19,and is directed to the grid electrode of vacuum detector tube 20 througha grid resistor 21 and associated grid leak and condenser 22. Tuningcondenser 23 is associated with transformer 18 in the conventionalmanner. The output terminals of primary windings of transformersll and18 are connected to the positive terminal of a B battery throughconductor 24 and variable resistance 25. The secondary windings oftransformers 2, 11 and 18 may be connected together by a conductor 26and suitably grounded, as at 27, 28 and 29.

\Vhen a switch arm 30 is thrown, so as to connect together contactpoints 31 and 32 and contact points 33 and 34 current flows from the Abattery and conductor 35, through a conductor 36, and through thefilament circuits of vacuum tubes 9, 14 and 20. Appropriate resistancesof either a fixed or variable nature, as resistances 37, 38 and 39 maybe inserted in the filament circuits to control the filament voltage.

When contact points 31 and 32 are connected by switch arm 30, outputenergy from the plate of vacuum detector tube 20 passes throughconductor 40, through conductor 41 and through the primary winding 42 ofan audio transformer 43. Energy induced into the secondary winding 44 oftransformer 43 is then directed through conductor 45 to the gridelectrode of audio amplifier tube 46. Energy leaves the plate electrodeof tube 46 through conductor 47 and passes through the primary winding48 of a second transformer 49. The primary windings 42 and 48 areconnected by means of conductors 50 and 51 to a B battery through chokecoil 52, the B battery serving as a source of plate potential fordetector tube 20 and audio tube 46. A con duetor 53 connects the plateelectrode of detector tube 20 through a small condenser 54 to thenegative terminal of the A battery.

Energy transferred to the secondary winding 55 of transformer 49 isdirected through a potentiometer 56 arranged to control the potential onthe grid of audio tube 57. Output energy from the plate electrode oftube 57 is directed through conductor 58 to out put terminal 59 of thereceiving system after first passing through a filter comprising shuntinductance 60 and series capacity 61.

The secondary windings of transformers 43 and 49 are connected byconductors 62 and 63 tothe terminals of C batteries in a conventionalmanner.

When switch 64 is closed, current constantly flows through the filamentcircuits of audio tubes 46 and 57, and they remain lighted. A smallcondenser 65 of 4 microfarad capacity may be shunted between theterminal of the A and B battery, in the convent-ionaLmanner, to obtainfiner control over the current flow. One output terminal 66 of thereceiving system is connected through conductor 67 to a B battery, andthe other output terminal 59 is connected to the plate electrode ofvacuum tube 57, as already explained.

When contact points 31 and 32, 33 and 34 are connected, it is seen thatthere is presented a complete radio apparatus operative to receive radiowaves and to translate them into apulsating current of audio frequencyoutput through output terminals 59 and 66.

My recording device, illustrated diagrammatically in Fig. 2, operates toimpress upon and 69, which are plugged into the output terminals 59 and66 of the radio receiving apparatus. The pulsating current of audiofrequency from plugs 68 and 69 is directed to the secondary winding 700f a transformer T1, bearing a two to one ratio, through conductors 72and 73. Energy induced into the primary winding 74 of the transformer isdirect-ed to the secondary winding 7 5 of a sec ond transformer 76, ofapproximately fourteen to one ratio, through conductors 77 and 78. Oneend of the primary winding 79 of transformer 76 is connected to twoplugs 80 and 81 through conductors 82 and 83, and the other end ofprimary winding 79 is connected to plug 84 through conductor 85.Although one transformer can be used in place of the two transformers 71and 76, much better recording results are obtained by the use of twotransformers connected as above outlined.

I have represented my recording head con taining the electromagnets formagnetizing the wire diagrammatically at 100; the structure of myrecording head having been disclosed in my prior Patents No. 1,612,359and Reissue No. 16,586, and forms no part of this invention. Therecording head is provided with an upper and a lower electromagnet, eachprovided with a primary and secondary winding, each secondary windinghaving many more turns than the corresponding primary winding. Whenplugs 80 and 84 are placed in their corresponding sockets 86 and 87, thepulsatin current, induced into primary winding 79, flows from terminal87 through conductor 88, through primary winding 89 of an induction coil90, preferably of the closed core type, through conductor 91, throughthe battery K, and thence through conductor 92 to socket terminal 86.Conductor 91 also connects to a resistance R, the other side of which isconnected by conductors 93 and 94 through binding post 95 to the primary96 of the erasing and polarizing coil. The negative terminal of batteryK is connected by conductor 92, through sockets 86 and 97 to conductors98, 99 and 101 to the primary winding 102 of the upperrecordingelectromagnet 103 of recording head 100. Primary win-ding 102is connected to the primary winding 104 of lower recording magnet 105.to conductor 106, to primary winding 107 of lower erasing and polarizingmagnet 108, and to primary winding 96 of upper erasing and polarizingmagnet 109 of erasing and polarizing head 110. Thus it is seen that auniform direct current flows from the positive side of battery K throughprimary windings 96 and 107 of upper and lower erasing and polarizingmagnets 109 and 108, and thence through primary windings 104 and 102 oflower and upper recording magnets 105 and 103 back to the negative sideof battery K. The current flow may be controlled by the variableresistance R.

The pulsating audio frequency current induced into the secondary winding111 of induction coil 90 is directed through conductors 98, 99 and 101through the secondary winding 112 of upper recording magnet 102 throughthe secondary 113 of lower recording magnet 105, through conductor 114and back to the secondary winding, forming a complete electric circuitfor the pulsating current.

The pulsating current in the secondary windings 112 and 113inducessimilar pulsations in the direct current flowing through primarywindings 102 and 104 of the upper and lower recording heads. As aresult, the cores of the recording electromagnets 103 and 105 will bemagnetized with an intensity which varies at each moment in accordancewith the fluctuations of the current in circuit 98 and 114. A metalribbon or wire passing between the core pieces of upper and lowermagnets 103 and 105 will have corresponding variations of magneticintensity impressed thereon. The wire passing through the recording-head 100 will thus be magnetized in the desired manner, and a magneticsound record of the program received over the radio will be impressedthereon. Erasing magnets 108 and 109 are for the purpose of removing anymagnetism already in the wire before it enters the recording head, asexplained in my prior patents above referred to. Upper and lowerelectromagnets 103 and 105 constituting the recording head 100 are sowound as to develop an impedance of approximately 50 ohms, while theupper and lower magnets 109 and 108 of erasing and polarizing head 110are so wound as to develop an impedance of approximately 17 ohms.

It is seen that in recording sound, no current flows through thesecondary windings 115 and 116 of the upper and lower windings of theerasing and polarizing head 110. Current flows, however, through theprimary coils 96 and 107 of the erasing and polarizing head 110 whichoperate to uniformly magnetize the core pieces within these primarycoils. Since the wire first passes through the erasing and polarizinghead 110, any magnet-ism that may be in the wire is neutralized and theWire given a uniform polarity by the core pieces within the upper andlower primary coils 96 and 107. The wire, with the magnetic sound recordof the radio program impressed there on, may be wound upon a spool andstored for future reproduction on my apparatus, as will now bedescribed.

Head 100 is used as a part of the reproduc- 113. This fluctuatingcurrent is directed to sockets 118 and 12 1 through conductors 99 and122 and through conductors 125 and 126 and binding post 127.

The magnetized sound recording wire is generally run through both heads110 and 100 and by so doing the fluctuating current strength can beincreased with corresponding increased volume of the reproduced sound.Considering head 110 as also a part of the reproducing unit, when themagnetic material carrying a magnetic sound record is progressed betweenthe pole pieces of the upper and lower electromagnets 109 and 108, anelectric current which fluctuates in accordance with the variations ofmagnetic intensity in the magnetized material will be induced in thesecondary windings 115 and 116 of the upper and lower electromagnets 109and 108. This pulsating or fluctuating current induced in the secondarywindings isdirected to sockets 117 and 118 through conductors 119 and120 and binding post 121 and through conductors 99 and 122 and bindingpost 123. It is seen that when both heads 110 and 100 are used, theinduced current flowing from secondary winding 115 of head 100 passesinto conductor 99 where it is joined or added to the induced currentfrom the secondary winding 102 flowing through conductor 101 and alsointo conductor 99. Although the magnets of heads 110 and 100 are spacedapproximately 34 of an inch apart, in actual practise approximatelythree feet of magnetized wire are required to reproduce, for instance,the sound characteristics of a. It is therefore seen that theinterference between the magnets in the respective heads is negligible,and practically they cooperate together to increase the sound volume.All interference can of course be eliminated by using a suflicientlywide sound recording wire or band and placing the magnets on oppositesides of the band.

\Vhen reproducing, the wire carrying the magnetic sound record istherefore preferably run between both pole pieces of heads 110 and 100,as above described. Plugs 128, 129 and 130 are plugged into theirrespective sockets 117, 118 and 124, and terminals 131 and 1.32 areconnected to jack terminals 133 and 134. Switch handle 30 is thrown soas to connect terminal 135 with 136 and terminal 137 with 138. Thepulsating direct current of audio frequency is thus directed to the jackterminals 133 and 134, one of which is connected with a source offilament potential through conductor 139. The other terminal 133 of thejack is connected through conductor 140 to the grid electrode of avacuum tube 141, through which the pulsating current produced by themagnetized wire is directed. When terminals 137 and 138 are connected,the filament circuit of tube 141 is closed, current flowing from thepositive terminal of the A battery through conductors 35 and 143,through the filament, through conductor 144, through a variableresistance 145, through conductor 139, and back to the negative terminalof the A battery.

Output energy from the plate electrode of tube 141 is then directedthrough conductor 142 and 146 and through the primary winding 42 of theaudio transformer 43. The audio pulses are then transferred, in a mannersimilar to that described in connection with the reception of *adiofrequency energy. by having the amplified energy directed throughamplifying audio tubes 46 and 57 and thence to the speaker terminals 59and 66. It will be noted that when switch 30 is moved to connectterminals 31 and 32, 33 and 34, the detector tube 142 has its platecircuit open. When switch arm 30 is moved to connect terminals 135 and136, 137 and 138, then the output circuits of detector tube 20 and itsassociated radio frequency amplifier tubes 9 and 14 are open. Theterminals 33 and 34, 137 and 138 open and close the filament circuits,terminals 33 and 34 controlling the filament circuits of amplifier tubes9 and 14 and detector tube 20, and terminals 137 and 138 control thefilament circuit of amplifier tube 141.

If a loud speaker or phones are connected to terminals 59 and 66, withswitch 30 moved to cover contact points 31 and 32, 33 and 34, theapparatus may be used as the ordinary radio set for the reception ofradio programs.

. With terminals 68 and 69 plugged into sockets 59 and 66, the radioprogram may be recorded on the wire in the form of a magnetic soundrecord.

My apparatus is also adapted to record sound other than that received byradio waves. To record any sound, a microphone is plugged into sockets86, 87 and 97. The wave, characteristics of the sounds secured by themicrophone produce fluctuations in the direct current flowing frombattery K. This fluctuating current, flowing through primary winding 89of induction coil 90, induces a corresponding fluctuating current insecondary winding 111. This fluctuating or pulsating current istranslated into a magnetic sound record on the wire in the manneralready described in connection with the recordation of radio programs.

It is thus seen that I have provided an apparatus by means of whichradio programs may be received and permanently recorded, to be laterreproduced as desired. Sounds other than those received by radio wavesmay also be recorded and reproduced by my apparatus in the same manner.

As many changes could be made in the above construction and as manywidely different embodiments of this invention could be made withoutdeparting from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

lVhat I claim is 1. Apparatus for recording and reproducing naturalsounds, including, in combination, electro-magnetic recording meansincluding an electro-magnet having co-axial primary and secondarywindings, a source of direct current connected with said primary windingto flow therethrough, means for converting received radio frequencyenergy modulating in correspondence with natural sounds intocorrespondingly modulating audio frequency electric current,meansdirecting said current to flow through the secondary winding of saidelectromagnet to modulate the intensity of the magnetic field of saidmagnet in correspondence with the modulations of said current, amagnetizable record carrier, and means for moving said magnetizablerecord carrier through the field of said magnet to place on said recordcarrier magnetic impressions modulating therealong in correspondencewith said received modulating radio frequency energy, whereby saidrecord carrier is conditioned for magnetic reproduction therefrom of thesounds governing the modulations of said received radio frequencyenergy. I

2. Apparatus forrecording and reproducing natural sounds, inc1uding,incombination, electro-magnetic recording means including anelectro-magnet having co-axial primary and secondary windings, a sourceof direct current connected with said primary winding to flowtherethrough, means for converting received radio frequency energymodulating in correspondence with natural sounds into correspondinglymodulating audio frequency electric current, means directing saidcurrent to flow through the secondary winding of said electro-magnet tomodulate the intensity of the magnetic field of said magnet incorrespondence with the modulations of said current, a magnetizablerecord carrier, means for moving said magnetizable record carrierthrough the field of said magnet to place on said record carriermagnetic impressions modulating therealong in correspondence with saidreceived modulating radio frequency energy, and means forelectromagnetically reproducing from said record carriersoiindscorresponding to the magnetic impressions thereon.

3. Apparatus for recording and reproducing natural sounds, including, incombination, electro-magnetic recording means including anelectro-magnet having co-axial primary and secondary windings, a sourceof direct current connected with said primary winding to flowtherethrough, means for C0111 verting received radio frequency energymodulating in correspondence with natural sounds into correspondinglymodulating audio frequency electric current, means directing saidcurrent to flow through the secondary winding of said electro-magnet tomodulate the intensity of the magnetic field of said magnet incorrespondence with the modulations of said current, a magnetizablerecord carrier, means for moving said magnetizable record carrierthrough the field of said magnet to place on said record carriermagnetic impressions modulating there'along in correspond ence with saidreceived modulating radio frequency energy, and means including saidelectro-magnet for reproducing from said record carrier soundscorresponding to the magnetic impressions on the carrier.

4. In an apparatus for recording and reproducing sounds, in combination,a radio receiver having an output circuit, a pickup tube havingvan inputcircuit and an output circuit, an amplifier having an input circuit, anda single switch whereby the output circuit of the radio receiver and theoutput circuit of the pick-up tube may be selectively connected with theinput circuit of the amplifier in accordance with the adjustment of theswitch, a telegraphone device, including a recording and reproducingelectro-magnet, having primary and secondary windings, a source ofcurrent of uniform intensity, means for causing said current to fiowthrough the primary winding of said electro-magnet to condition themagnet for recording action and a circuit through the secondary windingof said electro-magnet, and means for electrically connecting saidcircuit through said secondary winding with the output circuit of saidamplifier.

5. In an apparatus for recording and reproducing sounds, in combination,a radio receiver having an output circuit, a pick-up tube having aninput circuit, and a single switch whereby the output circuit of theradio receiver and the output circuit of the pick-up tube may beselectively connected with the input circuit of the amplifier inaccordance with the adjustment of the switch, a telegraphone device,including a recording and reproducing electro-magnet, having primary andsecondary windings, a source of current of uniform intensity, means forcausing said current to flow through the primary winding of saidelectro-magnet to condition the magnet for recording action and acircuit through the secondary winding of said electro-magnet, and meanswhereby said circuit through said secondary winding may be connectedselectively with the output circuit of received radio broadcast; acircuit including 7 the microphone, audio frequency amplifier andtelegraphone head for telegraphonic recording of audible sounds; and acircuit including the telegraphone head, pick up tube, audio frequencyamplifier and loud speaker for audible telegraphonic reproduction.

, This specification signed this 28th day of April, 1928.

HARRY E. CHIPMAN.

